Electrical Power System

Abstract

The present disclosure describes an electrical power system that comprises an electrical load having a multi-turn winding that has a first portion having a first plurality of turns and a second portion having a second plurality of turns. The system also comprises a first converter for supplying a first AC current to the first portion and the second portion of the multi-turn winding and a second converter for supplying a second AC current to the second portion of the multi-turn winding.

1 . An electrical power system, comprising:
 an electrical load comprising a multi-turn winding that has:
 a first portion having a first plurality of turns; and 
 a second portion having a second plurality of turns; 
   a first converter for supplying a first AC current to the first portion and the second portion of the multi-turn winding; and   a second converter for supplying a second AC current to the second portion of the multi-turn winding,   wherein the first converter and the second converter are for coupling to the same DC power source.   
     
     
         2 . The electrical power system of  claim 1 , wherein the second converter is for supplying the second AC current to the second portion of the multi-turn winding when the electrical load is operating at low power, and
 wherein the first converter is for supplying the first AC current to the first portion and the second portion of the multi-turn winding when the electrical load is not operating at low power.   
     
     
         3 . The electrical power system of  claim 2 , wherein the second converter and the second portion of the multi-turn winding are optimised for electrical efficiency at low power. 
     
     
         4 . The electrical power system of  claim 2 , configured such that when the electrical load is operating at low power, only the second AC current is supplied to the multi-turn winding. 
     
     
         5 . The electrical power system of  claim 2 , further comprising:
 a controller configured to:
 determine whether the electrical load is operating at low power based at least one measure of electrical load performance that is indicative of power and at least one pre-determined range of values defining a low power level; and 
 control the first converter and the second converter based on the determination of whether the electrical low is operating at low power. 
   
     
     
         6 . The electrical power system of  claim 5 , wherein the at least one measure of electrical load performance that is indicative of power comprises at least one of:
 a measure of mechanical power of the electrical load;   a speed of the electrical load;   a torque of the electrical load;   a measure of electrical current supplied to the electrical load;   a measure of electrical current supplied by the DC power source; or   a frequency of electrical current and/or voltage supplied to the electrical load.   
     
     
         7 . The electrical system of  claim 4 , wherein the system is configured such that when the electrical load is not operating at low power, only the first AC current is supplied to the multi-turn winding. 
     
     
         8 . The electrical system of  claim 4 , wherein the system is configured such that when the electrical load is operating at mid power, only the first AC current is supplied to the multi-turn winding and the second converter is turned off, and
 when the electrical load is operating at high power, both the first AC current and the second AC current are supplied to the multi-turn winding.   
     
     
         9 . An electrical power system, comprising:
 an electrical load comprising a multi-turn winding that has:
 a first portion having a first plurality of turns; and 
 a second portion having a second plurality of turns; 
   a first power supply for supplying a first AC current to the first portion and the second portion of the multi-turn winding;   a second power supply for supplying a second AC current to the second portion of the multi-turn winding; and   a controller coupled to the first power supply and the second power supply and configured to:
 determine a power level of the electrical load; and 
 control the first power supply and the second power supply based at least in part on the determined power level of the electrical load. 
   
     
     
         10 . The electrical power system of  claim 9 , wherein the controller is configured to determine the power level of the electrical load based on at least one measurement associated with the electrical load that is indicative of power, and
 wherein the controller is configured to determine whether the power level of the electrical load is high using a first pre-determined range of power levels that are defined as high power levels.   
     
     
         11 . The electrical power system of  claim 10 , wherein the at least one measurement associated with the electrical load that is indicative of power comprises at least one of:
 a measure of mechanical power of the electrical load;   a speed of the electrical load;   a torque of the electrical load;   a measure of electrical current supplied to the electrical load;   a measure of electrical current supplied by the DC power source; or   a frequency of electrical current supplied to the electrical load.   
     
     
         12 . The electrical power system of  claim 9 , wherein the controller is configured to turn on both the first power supply and the second power supply to supply first AC current and second AC current to the multi-turn winding when the determined power level of the electrical load is high. 
     
     
         13 . The electrical power system of  claim 9 , wherein the controller is configured to turn on only the second power supply to supply only the second AC current to the multi-turn winding when the power level of the electrical load is low. 
     
     
         14 . The electrical power system of  claim 13 , wherein the controller is configured to determine whether the power level of the electrical load is low using a second pre-determined range of power levels that are defined as low power levels. 
     
     
         15 . The electrical power system of  claim 13 , wherein the second plurality of turns and the second power supply are optimised for electrical efficiency when the power level of the electrical load is low. 
     
     
         16 . The electrical power system of  claim 10 , wherein the first power supply and the second power supply are couplable to the same DC power source, or
 wherein the first power supply is couplable to a first DC power source and the second power supply is couplable to a second DC power source.   
     
     
         17 . The electrical power system of  claim 10 , wherein the controller is configured to control the first power supply and the second power supply based further on one or more of: at least one temperature measurement associated with the first power supply or at least one temperature measurement associated with the second power supply. 
     
     
         18 . The electrical power system of  claim 10 , wherein one or more of a cross-sectional size, a cross-sectional shape, or a material of a conductor making up the first plurality of turns is different to one or more of: a cross-sectional size, a cross-sectional shape, or a material of a conductor making up the second plurality of turns. 
     
     
         19 . The electrical power system of  claim 10 , wherein the second converter is configured to generate more voltage levels in its AC output than the first converter, or
 wherein the second power supply is configured to generate more voltage levels in its AC output than the first power supply.   
     
     
         20 . An electric vehicle comprising an electrical power system, the electrical power system comprising:
 an electrical load comprising a multi-turn winding that has:
 a first portion having a first plurality of turns; and 
 a second portion having a second plurality of turns; 
   a first converter for supplying a first AC current to the first portion and the second portion of the multi-turn winding; and   a second converter for supplying a second AC current to the second portion of the multi-turn winding,   wherein the first converter and the second converter are for coupling to the same DC power source.